<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>Title</title>
</head>
<body>

<div id="app">
  <h2>当前计数: {{counter}}</h2>
  <button v-on:click="counter++">+</button>
  <button v-on:click="counter--">-</button>

<!--  <button v-on:click="add">+</button>-->
<!--  <button v-on:click="sub">-</button>-->
  <!--下面是语法糖写法-->
<!--  <button @click="counter&#45;&#45;">-</button>-->
</div>


<script src="../js/vue.js"></script>
<script>
  const app = new Vue({
    el: '#app',
    data: {
      counter: 0
    },
    methods: {
      add: function () {
        this.counter++;
      },
      sub: function () {
        this.counter--;

      }
    }
  })
</script>
</body>
</html>
